1. Field of the Invention
The invention relates to a panel structure of a surface-discharge-type alternating-current plasma display panel.
The present application claims priority from Japanese Applications No. 2002-1313, the disclosures of which are incorporated herein by reference for all purposes.
2. Description of the Related Art
In recent years, surface-discharge-type alternating-current plasma display panels (hereinafter referred to as xe2x80x9cPDPxe2x80x9d) have been receiving attention as slim, large sized color screen displays, and are becoming increasingly common in homes and the like.
Such PDPs typically include a front glass substrate and a back glass substrate opposite to the front glass substrate with a discharge space in between.
The front glass substrate is provided on its back surface with a plurality of row electrode pairs regularly arranged in the column direction and each extending in the row direction to form a display line, and a dielectric layer covering the row electrode pairs.
The back glass substrate is provided on the surface facing the front glass substrate with a plurality of column electrodes regularly arranged in the row direction and each extending in the column direction to intersect the row electrode pairs.
Thus, discharge cells are respectively formed at areas in the discharge space corresponding to the intersections of the column electrodes and the row electrodes. Red, green and blue phosphor layers are provided inside the individual discharge cells in the order of red, green and blue colors.
In the operation of the PDP for displaying an image, in an addressing period following a reset period for carrying out a reset discharge, an addressing discharge is selectively caused between one row electrode in the row electrode pair and the column electrode opposite the one row electrode in the individual discharge cell, for distribution of lighted cells (the discharge cell having wall charges formed on the dielectric layer) and non-lighted cells (the discharge cell having no wall charges formed on the dielectric layer) over the panel surface in accordance with an image to be displayed.
In a sustaining emission period following the addressing period, a discharge sustaining pulse is applied alternately to the paired row electrodes of the row electrode pairs in all of the display lines in order to excite the wall charges on the dielectric layer in each lighted cell to cause a sustaining discharge between the paired row electrodes. Then, ultraviolet light generated by the sustaining discharge excites the red, green or blue phosphor layer in each discharge cell to allow it to emit light for the generation of a display image.
In the prior art PDPs having a construction as described above, the addressing discharge occurs across the same discharge cell with the interposition of the red, green or blue phosphor layer as the sustaining discharge occurring in it. For this reason, the addressing discharge is subjected to influences ascribable to the phosphor layer, such as discharge properties varying among the phosphor materials of the three colors forming the phosphor layers, variations in the thickness of the phosphor layers produced in the manufacturing process for the PDP, and the like. Hence, the prior art PDPs have a significant difficulty in ensuring uniform addressing discharge properties among the individual discharge cells.
The prior art PDPs as described above needs a large discharge space in each discharge cell for an increase in the luminous efficiency. If a partition wall defining the discharge cells is increased in height for increasing the luminous efficiency, then this means an increase in the interval between the row electrode and the column electrode between which the addressing discharge is produced. This increased interval produces a problem of an increase in the starting voltage for the addressing discharge.
To solve the problems associated with the prior art as described above, the applicant of the present application suggested a PDP having the following structure in Japanese Patent Application No. 2001-213846 filed prior to the present application.
As illustrated in FIG. 9 and FIG. 10, the suggested PDP includes a partition wall 15 formed on the surface of a back glass substrate 13 facing the display screen and including first transverse walls 15A, second transverse walls 15B and vertical walls 15C. The first transverse walls 15A and the vertical walls 15C of the partition wall 15 partition the discharge space defined between a front glass substrate 10 and the back glass substrate 13 into discharge cells.
Each of the discharge cells is divided into two cells by the second transverse wall 15B: a display discharge cell C1a opposite transparent electrodes Xa and Ya of a row electrode pair (X, Y), and an addressing discharge cell C2a opposite back-to-back bus electrodes Xb and Yb of the adjacent row electrode pairs (X, Y). The display discharge cell C1a and the addressing discharge cell C2a are adjacent to each other in the column direction on either side of the second transverse wall 15B, and communicate with each other by means of a clearance rxe2x80x2 formed between the front face of the interposed second transverse wall 15B and a protective layer covering an additional dielectric layer 12.
A protrusion rib 17 protrudes from a portion of the back glass substrate 13 facing each addressing discharge cell C2a into the addressing discharge cell C2a, to raise the corresponding part of the column electrode D in the direction of the inside of the addressing discharge cell C2a. Hence, a space-distance s2 between the part of the column electrode D and the bus electrode Yb facing the addressing discharge cell C2a is smaller than a space-distance s1 between a part of the column electrode D and the transparent electrode Ya facing the display discharge cell C1a. 
In the suggested PDP, when a scan pulse is applied to the row electrodes Y and a data pulse is applied to the column electrodes D in the addressing period following the reset period, the addressing discharge occurs within the addressing discharge cell C2a because the space-distance s2 between the bus electrode Yb of the row electrode Y and the column electrode D opposite to each other on either side of the addressing discharge cell C2a is smaller than the space-distance s1 between the transparent electrode Ya of the row electrode Y and the column electrode D opposite to each other on either side of the display discharge cell C1a. 
Charged particles generated through the addressing discharge in the addressing discharge cell C2a pass through the clearance rxe2x80x2 to flow into the display discharge cell C1a which is adjacent to the addressing cell C2a concerned, with the second transverse wall 15B in between. Thus, lighted cells and non-lighted cells are distributed in all of the display lines L on the panel in accordance with an image to be displayed.
FIG. 11 shows another construction of the suggested PDP described thus far. The PDP shown in FIGS. 9 and 10 includes the protrusion rib 17 provided for raising the column electrode D inside the addressing discharge cell C2a, whereas the PDP shown in FIG. 11 includes a column electrode Dxe2x80x2 having a conventional linear shape, and a dielectric layer 18 formed of high xcex5 (epsilon) materials is formed in an addressing discharge cell C2xe2x80x2a to reduce the virtual discharge-distance between the column electrode Dxe2x80x2 and the bus electrode Yb between which the addressing discharge is created.
However, both PDPs constructed as described above have a problem of a reduction in margins at the addressing discharge if variations in the space-distances s2 between the bus electrode Yb and the column electrode Dxe2x80x2 raised in the addressing discharge cell C2a by the protrusion rib 17 (see FIG. 10) or in the discharge space between the bus electrode Yb and the surface of the high xcex5 (epsilon) materials-made dielectric layer 18 formed in the addressing discharge cell C2xe2x80x2a (see FIG. 11), are produced when the PDP is manufactured.
The above PDP has an arrangement of row electrodes Y provided with a scan pulse for the addressing discharge between itself and the column electrode D and row electrodes X not-involved in the addressing discharge in alternate positions in the column direction. Therefore, there is another problem of an increase in reactive power resulting from the discharge capacity formed in the non-display area between the back-to-back row electrodes X and Y of the adjacent row electrode pairs (X, Y) in the column direction when a sustaining pulse is alternately applied to the row electrodes X and Y of the row electrode pair (X, Y) to cause the sustaining discharge.
The present invention has been made to solve the problems associated with the prior art surface-discharge-type alternating-current plasma display panel as described above.
Accordingly, it is an object of the present invention to provide a surface-discharge-type alternating-current plasma display panel achieving the stabilization of the addressing discharge properties in each discharge cell, and also a reduction in discharge starting voltage for an addressing discharge and in reactive power produced at the sustaining discharge.
To attain the above object, the present invention provides a plasma display panel including: a front substrate; a plurality of row electrode pairs regularly arranged in a column direction on a back surface of the front substrate, and each extending in a row direction to form a display line and constituted by first and second row electrodes; a back substrate placed opposite the front substrate with a discharge space intervening between; and a plurality of column electrodes regularly arranged in the row direction on a surface of the back substrate facing toward the front substrate, and each extending in the column direction to intersect the row electrode pairs and form unit light-emitting areas in the discharge space at the respective intersections. The plasma display panel according to a first feature of the present invention comprises: a first discharge area provided in each of the unit light-emitting area and facing opposed parts of the first and second row electrodes to provide for a discharge between the first and second row electrodes; and a second discharge area provided in each of the unit light-emitting area and facing a part of the first row electrode, positioned opposite to a part thereof opposing the second row electrode and creating a discharge in association with the column electrode, to provide for a discharge between the part of the first row electrode and the column electrode, the first discharge areas and the second discharge areas in the individual unit light-emitting areas being arranged in alternate positions in the column direction so that the second discharge areas of the respective unit light-emitting areas adjacent to each other are arranged in a back-to-back position in the column direction.
The plasma display panel in the first feature includes unit light-emitting areas each divided into two areas: the first discharge area experiencing a sustaining discharge created between the opposed parts of the first and second row electrodes constituting the row electrode pair to produce visible light for the generation of an image, and the second discharge area experiencing an addressing discharge created between the column electrode and the first row electrodes in the row electrode pair to establish lighted cells (the first discharge areas having wall charges formed therein) and non-lighted cells (the first discharge areas having no wall charges formed therein) over the panel surface. Charged particles produced by the addressing discharge in the second discharge area divided from the first discharge area transfer from the second discharge area into the first discharge area forming the same unit light-emitting area together with the second discharge area concerned. Thus, the lighted cells and the non-lighted cells are distributed over the panel surface of the plasma display panel in accordance with an image to be displayed.
After that, a sustaining pulse is applied alternately to the first row electrode and the second row electrode constituting each row electrode pair, whereupon a sustaining discharge occurs in the lighted cells, and the phosphor layers of the three primary colors, red, green and blue, formed in the individual first discharge areas are excited to emit light. The image is thus generated on the panel surface in response to an image signal.
In the plasma display panel, the positions of the first discharge areas and the second discharge areas in the individual unit light-emitting areas in a column direction are transposed alternately between adjacent display lines so that the second discharge areas of the adjacent unit light-emitting areas are arranged back to back with each other in the column direction. This arrangement allows alternate transposition of the first row electrode and the second row electrode in each of the row electrode pairs in adjacent display lines in the column direction. Hence, the row electrodes of the row electrode pairs are arranged with the same-type electrodes in back-to-back position in the column direction.
According to the first feature, in this way the addressing discharge between the column electrode and the first row electrode is created in the second discharge area which is separated from the first discharge area provided for the sustaining discharge between the first and second row electrodes of the row electrode pair. Hence, it is unnecessary for a phosphor layer for generating visible light to be formed in the second discharge area. The present invention successfully frees the addressing discharge in the second discharge area from the conventionally disadvantageous influences produced by the phosphor materials different among the colors forming the phosphor layers and the variations in the thickness of the phosphor layers, thus providing stabilized discharge properties of the addressing discharge.
The arrangement of the second discharge areas for the addressing discharge in a back-to-back position in the column direction makes it possible to arrange the same-type electrodes of the row electrodes, constituting the individual row electrode pairs, in a back-to-back position in the column direction. Due to this arrangement, when a sustaining pulse is applied to the row electrode pairs to cause a sustaining discharge, discharge capacity is not formed in the non-display area located between the back-to-back row electrodes in the column direction, resulting in preventing the production of extra reactive power.
Further, even when the plasma display panel is designed to have a large discharge space in each first discharge area for an increase in the luminous efficiency, it is possible to reduce the discharge starting voltage for the addressing discharge because a discharge-distance between the column electrode and the row electrode which are opposite to each other across the second discharge area is adjustable at will.
To attain the aforementioned object, a plasma display panel according to a second feature comprises, in addition to the configuration of the first feature, a protrusion protruding from the back substrate in the direction of the front substrate and extending in the row direction, to establish a partition between the second discharge areas positioned back to back with each other in the column direction.
With the second feature, the protrusion protrudes from the back substrate between the back-to-back second discharge areas in between adjacent unit light-emitting areas in the column direction. The back-to-back second discharge areas are blocked from each other in the row direction by the protrusion. For this reason, the addressing discharges respectively created in the second discharge areas are prevented from having an effect on each other.
To attain the aforementioned object, a plasma display panel according to a third feature has, in addition to the configuration of the second feature, a configuration in which both side faces of the protrusion respectively facing the second discharge areas are inclined toward each other so as to narrow toward an leading end of the protrusion, and parts of the column electrode facing the second discharge areas follow the inclined side faces of the protrusion to protrude toward the front substrate, and the part of the column electrode inclined along each of the inclined side faces of the protrusion is opposite to the part of the first row electrode, positioned opposite to the part thereof opposing the second row electrode, to cause the discharge between the part of the column electrode and the corresponding part of the first row electrode.
The plasma display panel of the third feature is so constructed that the part of the column electrode opposite the first row electrode across the second discharge area for the addressing discharge is inclined along the inclined side face of the protrusion facing the second discharge area and projects toward the front substrate. Hence, a discharge distance between the first row electrode and the column electrode with the second discharge area intervening decreases or increases continuously in the column direction.
With the third feature, even if there are variations in the distance between the front substrate and the back substrate or in the height of the protrusion, a proper discharge distance is ensured between the row electrode and any point of the inclined part of the column electrode, to provide a stabilized addressing discharge.
To attain the aforementioned object, a plasma display panel according to a fourth feature, in addition to the configuration of the second feature, has a configuration in which a leading end of the protrusion is in contact with part of the front substrate to block the second discharge areas positioned back to back in the column direction from each other. The plasma display panel comprises: a dividing wall extending in the row direction and providing a division between the paired first and second discharge areas forming the unit light-emitting area, and a communication element provided between the dividing wall and the front substrate for communication between the paired first and second discharge areas.
With the fourth feature, the leading end of the protrusion formed between the back-to-back second discharge areas in the column direction is in contact with part of the front substrate to completely block the back-to-back second discharge areas from each other. However, between the first discharge area and the second discharge area which are paired with each other to form a single unit light-emitting area, there is provided a communication element between the front substrate and the dividing wall dividing off the paired first and second discharge areas from each other, to allow charged particles produced by the addressing discharge in the second discharge area to properly transfer into the first discharge area paired with the second discharge area concerned.
To attain the aforementioned object, a plasma display panel according to a fifth feature comprises, in addition to the configuration of the second feature, a shielding wall provided on a portion of the protrusion between the second discharge areas adjacent to each other in the row direction and projecting from both side faces of the protrusion to shield the adjacent second discharge areas in the row direction from each other.
With the fifth feature, the protrusion is provided with a shielding wall which projects from both the side faces of the protrusion respectively in the column directions to shield adjacent second discharge areas in the row direction from each other. This shield prevents the addressing discharge occurring in one second discharge area from spreading into another second discharge area adjacent thereto in the row direction, resulting in the proper introduction of charged particles produced by the addressing discharge into the first discharge area paired with the second discharge area concerned.
To attain the aforementioned object, a plasma display panel according to a sixth feature has, in addition to the configuration of the first feature, a configuration in which a part of the column electrode facing each second discharge area is increased in width.
With the sixth feature, the column electrode is designed to have an increased width in the part opposite to the row electrode on both sides of the second discharge area for the creation of the addressing discharge between the column and row electrodes, for an increase of an electrode area in order to stabilize the discharge properties of the addressing discharge. Further, selectively establishing the width of the column electrode facilitates the control of the amount of charged particles to be produced by the addressing discharge.
To attain the aforementioned object, a plasma display panel according to a seventh feature has, in addition to the configuration of the first feature, a configuration in which the first row electrode and the second row electrode which constitute each row electrode pair are alternately transposed in the column direction so that the first row electrodes of the adjacent row electrode pairs are arranged back to back and the second row electrodes are similarly arranged back to back.
With the seventh feature, the row electrodes constituting the row electrode pairs are arranged such that the same-type row electrodes are back to back in the column direction. Due to this arrangement, when a sustaining pulse is applied to the row electrode pair and the sustaining discharge occurs, discharge capacity is not formed in the non-display area located between the row electrodes in a back-to-back position in the column direction, which then prevents then occurrence of extra reactive power resulting from the sustaining discharge.
To attain the aforementioned object, a plasma display panel according to an eighth feature comprises, in addition to the configuration of the first feature, a black- or dark-colored light absorption layer provided on a portion of the front substrate opposite each of the second discharge areas.
With the eighth feature, when viewed from the front substrate, the non-display area on the panel corresponding to the second discharge areas is covered with the black- or dark-colored light absorption layer formed on the front substrate. This light absorption layer prevents the reflection of ambient light incident through the front substrate for an improvement in contrast in a displayed image, and also prevents the light emission generated by the addressing discharge in the second discharge area from leaking toward the display surface of the panel.
To attain the aforementioned object, a plasma display panel according to a ninth feature has, in addition to the configuration of the eighth feature, a configuration in which the light absorption layer is formed on the part of the first electrode opposite the column electrode with the second discharge area intervening between.
With the ninth feature, a black- or dark-colored light absorption layer is formed on the portion of the first row electrode opposite to the column electrode for the creation of the addressing discharge in the second discharge area, in order to prevent the reflection of ambient light incident on the non-display area of the panel for an improvement in contrast in a displayed image, and also to prevent the light generated by the addressing discharge in the second discharge area from leaking toward the display surface of the panel.
To attain the aforementioned object, a plasma display panel according to a tenth feature comprises, in addition to the configuration of the first feature, a phosphor layer provided only in the first discharge area for generating a visible light by means of a discharge.
With the tenth feature, a phosphor layer for generating a visible light by means of a discharge is formed only in the first discharge area, but not formed in the second discharge area. This construction allows the stabilization of the discharge properties of the addressing discharge because the addressing discharge occurring in the second discharge area is never subjected to the conventional disadvantageous influences produced by the phosphor materials different among the colors forming the phosphor layers and the variations in the thickness of the phosphor layers.
To attain the aforementioned object, a plasma display panel according to an eleventh feature comprises, in addition to the configuration of the first feature, a protrusion projecting from the back substrate toward the front substrate and extending in the row direction between the first discharge areas arranged in the column direction for creating a partition between the first discharge areas arranged in the column direction, in which the second discharge area is formed between a leading end face of the protrusion and the back surface of the front substrate, and the column electrode is projected toward the front substrate by the protrusion to allow a part of the column electrode projected toward the front substrate to be opposite to the part of the first row electrode, positioned opposite to the part thereof opposing the second row electrode, with the second discharge area intervening between.
In the plasma display panel of the eleventh feature, the protrusion functions as a partition wall for providing a boundary between the first discharge areas arranged in the column direction. In addition, the column electrode projected toward the front substrate by the protrusion is opposite the first row electrode with the second discharge area intervening which is formed between the leading end face of the protrusion and the back surface of the front substrate.
With the eleventh feature, the protrusion which forms the second discharge area between itself and the front substrate and causes the column electrode to project toward the front substrate and be opposed to the row electrode, functions as a partition wall for providing a boundary between the adjacent first discharge areas to eliminate the need for additionally providing a partition wall.
To attain the aforementioned object, a plasma display panel according to a twelfth feature comprises, in addition to the configuration of the eleventh feature, an additional element protruding from the front substrate backward to come in contact with a central position in the column direction of the leading end face of the protrusion, in order to block the second discharge areas positioned back to back in the column direction from each other.
With the twelfth feature, an additional element is formed on the front substrate side and opposite a central portion in the column direction of the leading end face of the protrusion to block the second discharge areas, which are formed in a back-to-back position between the protrusion concerned and the front substrate, from each other. This construction allows the proper introduction of charged particles, produced by the addressing discharge in the second discharge area, into the first discharge area paired with the second discharge area concerned.
To attain the aforementioned object, a plasma display panel according to a thirteenth feature has, in addition to the configuration of the eleventh feature, a configuration in which a part of the column electrode facing each second discharge area is increased in width.
With the thirteenth feature, the column electrode is designed to have an increased width in the part opposite to the row electrode on both sides of the second discharge area for the creation of the addressing discharge between the column and row electrodes, to increase an electrode area for the stabilized discharge properties of the addressing discharge. Further, selectively establishing the width of the column electrode facilitates the control of the amount of charged particles to be produced by the addressing discharge.
These and other objects and advantages of the present invention will become obvious to those skilled in the art upon review of the following description, the accompanying drawings and appended claims.